JP6212961B2 - Vehicle rear wheel steering device - Google Patents

Description

  The present invention relates to a vehicle rear wheel steering apparatus that is interposed in a suspension mechanism that supports a rear wheel of a vehicle and steers the rear wheel.

  Recently, various types of devices have been known as rear wheel steering devices constituting a part of a four-wheel steering system (4WS) of a vehicle. The basic configuration is described in Patent Document 1 below. From a "rod connected to the rear wheel of the vehicle, a housing supporting the rod and fixed to the chassis of the vehicle, and a motor housed in the housing and driving the rod to steer the rear wheel" Become. There are various types of suspension mechanisms for supporting the rear wheels of the vehicle, and various rear wheel steering devices are attached to the suspension mechanism. For example, the device described in Patent Document 2 below is not only different in basic configuration from the device described in Patent Document 1, but also includes a blocking device that intermittently transmits driving force from the electric motor to the push rod. It is supported by the module housing together with a motor and a transmission for converting its rotational movement into translational movement of the push rod. And the control unit which controls these is also mentioned.

Japanese Patent No. 5098242 Special table 2012-511465 gazette

  Since the apparatus described in Patent Document 2 is configured such that the electric motor, the transmission, and the blocking device are supported by the module housing, not only is the assembly difficult, but high strength is required for the housing. Miniaturization is difficult. Further, in Patent Document 2, the paragraph [0045] describes “an electric interface 65 forming a part of the circuit board of the control unit 20”, and further “a transmission cable extending to the bus line of the brake control unit or the CAN of the vehicle” The external electrical interface 2 is connected to the control unit 20 in a state of being joined to the cover 2 as is apparent from the disclosure of FIG. Therefore, it is necessary to provide a waterproof joint structure between the module housing and the cover, a waterproof joint structure between the cover and the external electrical interface, and a waterproof connector is required for joining the cable. On the other hand, although not explicitly disclosed in Patent Document 1, a controller (control unit) for driving and controlling a motor or the like is generally disposed in a case and attached to the housing. The space is a waterproof joint structure, and a large and expensive waterproof connector is used for joining with a cable including a power line and a signal line. In addition, since the position of the connecting portion where a waterproof structure is required is restricted, the degree of freedom in designing the circuit constituting the controller is limited.

  Therefore, the present invention provides a housing structure that can accommodate a controller appropriately and easily in a vehicle rear wheel steering apparatus that is interposed in a suspension mechanism that supports a rear wheel of a vehicle and steers the rear wheel, and is small and lightweight. It is an object of the present invention to provide a rear wheel steering device that can be used.

In order to achieve the above object, the present invention provides a rear wheel steering device for a vehicle that is interposed in a suspension mechanism that supports a rear wheel of a vehicle and steers the rear wheel. A housing connected via two connecting members, an electric motor accommodated in a cylinder constituting the housing, a reduction mechanism accommodated in the cylinder and decelerating the output of the electric motor, and coupled to the reduction mechanism. A nut member that rotates and a rod that is screwed to the nut member and connected to the second connecting member, and a linear motion mechanism that converts the rotational motion of the nut member into linear motion of the rod, and the housing And a housing that is disposed so as to surround the rod extending from the cylindrical body and is fixed to the cylindrical body, wherein at least one opening opening parallel to the rod is provided. While, the housing having a separate passage to the opening, and a lid joined to seal the opening of the housing, and a controller that said housed in the housing to drive and control the electric motor , a power line and a signal line electrically connected to the controller, the grommet holding surrounds the said power lines and signal lines, and a support bracket to which the grommet is mounted, said housing abuts said power line and the signal line It is connected to the controller in the body, led out to the outside through the communication hole, and the support bracket is fixed to the housing .

  The controller includes an electronic circuit board on which a plurality of elements that drive and control the electric motor are mounted, and a support board that supports the electronic circuit board with a predetermined gap and is fixed to the housing. It is preferable that the power line and the signal line are joined to the electronic circuit board in the housing.

Since this invention is comprised as mentioned above, there exist the following effects. That is, in the rear wheel steering device of the present invention, an electric motor housed in the cylinder, a speed reduction mechanism housed in the cylinder and decelerating the output of the electric motor, a nut member connected to the speed reduction mechanism and rotated, It has a rod that is screwed to the nut member and connected to the second connecting member, and surrounds the linear motion mechanism that converts the rotational motion of the nut member into the linear motion of the rod, and the rod that extends from the cylinder. A housing that is disposed and fixed to the cylinder, has at least one opening that opens in parallel with the rod, and has a communication hole separately from the opening, and an opening of the housing. A lid that is joined so as to be hermetically sealed, a controller that is housed in the housing and controls driving of the electric motor, a power line and a signal line that are electrically connected to the controller, and a grommet that surrounds and holds the power line and the signal line When, And a support bracket grommet is mounted, together with those of said power lines and signal lines are connected to a controller within the housing, is guided to the outside through the communication hole, the support bracket is fixed to the housing, Not only can the controller be accommodated in the housing appropriately and easily, but the circuit design can be performed without being restricted to the position of the connecting portion where a waterproof structure is required, and a conventional waterproof connector is required. And a waterproof structure that is easy to assemble and secure. In addition, since the housing in which the controller is accommodated does not need to have high strength, it can be a small , lightweight, and inexpensive device.

  In particular, the controller includes an electronic circuit board on which a plurality of elements that drive and control the electric motor are mounted, and a support board that supports the electronic circuit board with a predetermined gap and is fixed to the housing. If the power line and the signal line are joined to the electronic circuit board in the casing, the power line and the signal line can be easily and reliably joined to the electronic circuit board appropriately supported by the support board. .

1 is a cross-sectional view illustrating an overall configuration of a rear wheel steering apparatus according to an embodiment of the present invention. It is a cross-sectional view which expands and shows the actuator part in one Embodiment of this invention. It is a cross-sectional view which expands and shows the controller part in one Embodiment of this invention. It is a longitudinal cross-sectional view which expands and shows the controller part in one Embodiment of this invention. It is a top view which fractures | ruptures and shows the cover body of the controller part in one Embodiment of this invention.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows an overall configuration of a rear wheel steering apparatus according to an embodiment of the present invention. The rear wheel steering device of this embodiment constitutes a part of the four-wheel steering system (4WS), but the front wheel steering device is omitted because it is the same as before. There are various modes of suspension mechanisms for supporting the rear wheels of the vehicle. In this embodiment, the suspension mechanism is configured as shown by a two-dot chain line in FIG. 1, and supports the rear wheels RL and RR of the vehicle. An actuator unit AU constituting the rear wheel steering device of this embodiment is interposed between a support portion RS for the rear axle RA and a link LS that is pivotally supported by the rear axle RA and swings about the swing center C. As a result, the support portion RS and the link LS are telescopically driven, and the rear wheels RL and RR are steered via the tie rods TR and TR according to the swing of the link LS.

  The actuator unit AU is supported by the housing 1 so that the rod 2 can move in the axial direction (linear motion), one end of which is connected to the link LS via the ball joint JL, and the housing 1 is supported by the ball joint JA. It is connected to RS, and the rod 2 is driven by the actuator 3 so that the space between the support portion RS of the rear axle RA and the link LS is expanded and contracted. Specifically, the electric motor 3a constituting the actuator 3 is controlled by the controller 4, and after the rotational output of the electric motor 3a is decelerated by the speed reduction mechanism 3b, it is converted into a linear motion of the rod 2 via the linear motion mechanism 3c. It is configured to be. In the present embodiment, the electric motor 3a is a brushless motor.

  In the present embodiment, the housing 1 is roughly divided into a housing 1a that mainly contains components of the actuator 3 (electric motor 3a and the like) and a housing 1b that mainly contains components of the controller 4 (electronic circuit board 40 and the like). The connecting cover 11 is joined to the cylindrical body 10 constituting the housing 1a, and the housing 12 constituting the housing 1b and having openings in the vertical and axial directions is joined. The lids 15 and 16 are joined to the upper and lower openings 12x and 12y through O-rings (typically represented by OR) as seal members. The housing 1 of this embodiment is made of metal, the connection cover 11 and the housing 12 are made of aluminum, and the cylinder 10 and the lids 15 and 16 are made of iron.

  The actuator 3 is configured as shown in an enlarged view in FIG. 2, and is press-fitted and fixed in the cylindrical body 10 with the coil 23 wound around the stator 24. The output shaft of the electric motor 3 a is constituted by a hollow rotary shaft 20, which has an inner diameter portion 25 a of an annular motor cover 25 inserted into the cylindrical body 10 and an annular groove formed in the housing 12. 12a is rotatably supported via bearings 25b and 12b, respectively. A core 21 that constitutes the rotor of the electric motor 3 a is press-fitted and fixed to an intermediate portion in the axial direction of the hollow rotary shaft 20, and permanent magnets 22 are evenly arranged in the circumferential direction of the core 21.

  Further, the rod 2 is coaxially arranged in the hollow rotary shaft 20 and is supported so as to be movable in the axial direction (linear motion) with respect to the housing 1 and non-rotatably supported with respect to the housing 1. The structure will be described later. In addition, bushes 2a and 2b are interposed between the rod 2 and the support portion of the housing 12, but these reduce the sliding resistance in order to smoothly move the rod 2 in the axial direction. is there. That is, since this embodiment is a cantilever-supported expansion / contraction mechanism, the bushes 2a and 2b are not required to function as bearings in the axial movement mechanism supported at both ends.

  The speed reduction mechanism 3b of the present embodiment includes a planetary gear mechanism 30, and a sun gear 31 that is an external gear is integrally coupled to the hollow rotary shaft 20 and is rotatably supported together with the hollow rotary shaft 20. A ring gear 33 as an internal gear is fixed to a holder 34 as a cylindrical holding member, and a planetary gear 32 as an external gear meshes with the sun gear 31 and the ring gear 33 so as to rotate around the sun gear 31. . A nut member 36 is rotatably supported by a holder 34 via a bearing 37 as a carrier that rotatably supports the planetary gear 32 via a pin 35. The bearing 37 is a ball bearing, and an inner ring 37a is fitted to the nut member 36, and an outer ring 37b is fitted to the holder 34, and held by the nut member 36 by a C-shaped spacer 37c.

  In the present embodiment, the holder 34 and the pin 35 are made of metal (for example, iron), but the sun gear 31, the planetary gear 32, and the ring gear 33 are made of synthetic resin, and the sun gear 31 is integrally formed with the metal hollow rotary shaft 20. Has been. The ring gear 33 is supported so as not to rotate with respect to the holder 34, and the holder 34 is supported so as not to rotate with respect to the cylindrical body 10. That is, as shown in FIG. 2, the snap ring 14 is held in an annular groove 10 a formed in the cylindrical body 10, and a bearing 37 is interposed between the annular side surface of the snap ring 14 and the annular opening end surface of the connecting cover 11. In the state where the outer ring 37b and the holder 34 are sandwiched, the annular lock nut 13 is screwed into a screw portion formed at the opening end of the cylinder body 10 on the speed reduction mechanism 3b side (left side in FIG. 2). And the connection cover 11 is fastened. Thus, the outer ring 37b and the holder 34 of the bearing 37 are firmly held between the snap ring 14 and the connecting cover 11 by the axial pressing force generated with the screwing of the lock nut 13, and as a result, the holder 34 is held in a non-rotatable manner with respect to the cylindrical body 10.

  Then, a male screw portion 2 c formed with a trapezoidal screw over a predetermined axial length and a female screw portion 36 c formed on the inner peripheral surface of the nut member 36 are screwed onto the outer peripheral surface of one end portion of the rod 2. The nut member 36 and the rod 2 constitute a linear motion mechanism 3c. In order to prevent the rod 2 from falling off, a nut 2d is screwed to the tip of the male screw portion 2c. Since the rod 2 is supported as described above, the axial load that can be applied to the rod 2 is the cylindrical body 10 and the connecting cover 11 via the nut member 36, the bearing 37, the holder 34, and the snap ring 14. Absorbed in.

  On the other hand, as shown in FIG. 3, as the controller 4, an electronic circuit board 40 constituting an electronic control device (not shown) and a magnet block 50 constituting a displacement detection device 5 are accommodated in a housing 1b. The displacement detection device 5 includes a displacement sensor 5a composed of, for example, a magnetic vector sensor and a permanent magnet 5b composed of, for example, a neodymium magnet. The displacement sensor 5a is supported by the electronic circuit board 40, and the permanent magnet 5b is composed of a magnet block 50. Is held in. The magnet block 50 has a function of detecting axial displacement during linear movement of the rod 2 and a function of preventing the rotation of the rod 2 described above. Note that a plurality of elements (not shown) for driving and controlling the electric motor 3a are mounted on the electronic circuit board 40. As shown in FIG. 4, the electronic circuit board 40 is supported by a predetermined gap. The support substrate 60 is screwed to the housing 12.

  As shown in FIG. 3 and FIG. 4, long grooves (substantially rectangular recesses) 2 r and 2 s that are elongated in the axial direction are formed on both side surfaces of the rod 2, and a magnet block 50 is formed in one long groove 2 r. The bolt 51 is inserted from the long groove 2 s on the opposite side and fixed to the rod 2. The magnet block 50 is formed of a synthetic resin, and as shown in FIG. 3, a holding part 52 that houses the permanent magnet 5 b and a pair of leg parts 53, 53 are formed at both ends, and both leg parts 53, A metal nut 54 is insert-molded between 53. On the other hand, as shown in FIG. 4, a support portion 12 s is formed inside the housing 12, and a pair of standing wall portions 12 w and 12 w are formed in parallel to the axis of the rod 2. The holding portion 52 is assembled so as to be held between the pair of standing wall portions 12 w and 12 w, and the bolt 51 is inserted into the through hole 2 h of the rod 2 and screwed into the nut 54. As a result, the rod 2 is supported by the magnet block 50 so as not to rotate with respect to the standing wall portions 12 w and 12 w of the housing 12 and thus the housing 1. Note that FIG. 4 shows only the space on the lid 16 side where the electronic circuit board 40 is mounted, and the configuration in the space on the lid 15 side is omitted.

  Thus, in the actuator 3 of the present embodiment, when the hollow rotary shaft 20 is rotationally driven by the electric motor 3a, the rotational output is decelerated by the speed reduction mechanism 3b of the planetary gear mechanism 30, and the nut member 36 is rotationally driven. Furthermore, the rotational motion of the nut member 36 is converted into the linear motion of the rod 2 by the linear motion mechanism 3c. As a result, the support portion RS of the rear axle RA and the link LS are expanded and contracted as described above, and the steering angle of the rear wheels is adjusted.

FIG. 5 shows the center portion of the lid 15 in a cutaway manner in order to clarify the configuration in the space on the lid 15 side (omitted in FIG. 4) in the housing 12 constituting the housing 1b. Thus, power lines 80a and 80b and three signal lines (represented by 90 as a representative) are electrically connected to the electronic circuit board 40 constituting the controller 4. Specifically, the power lines 80 a and 80 b are directly connected to the connection terminals 81 a and 81 b provided at the respective ends by screws S, and the three signal lines 90 are connected to the electronic circuit board 40 via the connector 91. ing. In this case, as described above, the electronic circuit board 40 is supported by the support board 60 with a predetermined gap, and the support board 60 is screwed to the housing 12, so that the power lines 80a and 80b and the three wires are connected. The signal line 90 can be easily and reliably joined. Since the connector 91 is disposed in the housing 12 and does not need to have a waterproof structure, a small and inexpensive connector is used.

On the other hand, a communication hole H indicated by a broken line in FIG. 5 is formed in the housing 12 in addition to the openings 12x and 12y. The power lines 80a and 80b and the three signal lines 90 are connected to the communication hole H. A grommet 100 of a sealing material that is enclosed and held is attached to a support bracket 110, and the support bracket 110 is bolted to the housing 12. Thus, the power lines 80 a and 80 b and the three signal lines 90 are liquid-tightly supported in the communication hole H of the housing 12. The number of power lines and signal lines is not limited to the above, and may be one or more .

  The manufacturing method of the actuator unit AU having the above configuration will be described. First, the stator 24 around which the coil 23 is wound is press-fitted into the cylindrical body 10 by a press-fitting device (not shown), and the predetermined unit shown in FIG. Fixed in position. Further, the motor cover 25 is inserted into the cylindrical body 10, and the snap ring 14 is fixed to the annular groove 10 a in the cylindrical body 10. Separately from this, after the bearing 25b is press-fitted into the hollow rotary shaft 20 in which the sun gear 31 is integrally formed, a resin pressing member 22a for holding the permanent magnet 22 is press-fitted and the core 21 is press-fitted. Fixed. And the permanent magnet 22 is magnetized in the state of the subassembly in which the permanent magnet 22 is accommodated in the core 21 and the pressing member 22b is press-fitted.

  Next, the hollow rotary shaft 20 is inserted into the hollow portion of the stator 24, and the bearing 25 b is held in a state of being fitted into the hollow portion of the motor cover 25. Further, after the support member 26 to which the plastic magnet 6b for the magnetic pole sensor 6 is fixed is press-fitted into the end of the hollow rotary shaft 20 and the plastic magnet 6b is magnetized, the casing 12 is the electric motor 3a of the cylindrical body 10. It is joined to the opening on the side (right side in FIG. 2) and bolted. The outer ring of the bearing 12 b is press-fitted into the annular groove 12 a of the housing 12, and when the housing 12 is joined to the cylindrical body 10, the inner ring of the bearing 12 b is fitted to the hollow rotary shaft 20.

  On the other hand, the inner ring 37 a of the bearing 37 is fitted to the nut member 36 and held by the spacer 37 c, and the outer ring 37 b of the bearing 37 is fitted to the holder 34. Next, the ring gear 33 is attached to the holder 34, the planetary gear 32 is supported by the nut member 36 by the pin 35, and the locking member 38 is locked to the pin 35. Then, the male screw portion 2c of the rod 2 is screwed to the female screw portion 36c of the nut member 36, and the nut 2d is screwed to the tip of the male screw portion 2c to constitute a subassembly.

  The rod 2 of the subassembly is inserted into the hollow rotary shaft 20 shown in FIGS. 1 to 3, the sun gear 31 is assembled so as to mesh with the planetary gear 32 and the ring gear 33, and the axial end surface of the holder 34 is the snap ring 14. It is pushed in until it contacts the side end face. Subsequently, the connection cover 11 is attached, and the lock nut 13 is screwed into the cylinder 10. As a result, the outer ring 37 b of the bearing 37 and the holder 34 are firmly sandwiched between the snap ring 14 and the connection cover 11. At this time, the rod 2 passes through the bushes 2 a and 2 b provided in the housing 12 and extends to the outside of the housing 12.

  And in the housing | casing 12, the magnet block 50 is arrange | positioned in the long groove 2r of the rod 2, and it is assembled | attached so that the holding | maintenance part 52 may be hold | maintained between the standing wall parts 12w and 12w. Thus, when the bolt 51 is inserted into the through hole 2 h of the rod 2 and screwed into the nut 54, the rod 2 is supported so as not to rotate with respect to the housing 1.

  Furthermore, the electronic circuit board 40 on which the displacement sensor 5a is mounted and the support board 60 that supports the electronic circuit board 40 are accommodated in the housing 12, and the displacement sensor 5a is fixed at a position facing the permanent magnet 5b. Then, the power lines 80a and 80b and the three signal lines 90 are connected to the electronic circuit board 40, led out to the outside through the grommet 100 and the support bracket 110, and liquid-tightly supported in the communication hole H. When the bodies 15 and 16 are bolted to the housing 12 via the O-ring OR of the sealing member, the inside of the housing 12 becomes a liquid-tight space. After the assembly as described above, the ball joint JL is connected to the tip of the rod 2 and the rubber boot BT is mounted.

  Thus, since the inside of the housing 12 is configured as described above, not only can the controller 4 be accommodated in the housing 12 appropriately and easily, but the housing 12 in which the controller 4 is housed has high strength. Therefore, a small and lightweight device can be obtained. Moreover, it can be reliably waterproofed without the need for a conventional large waterproof connector.

DESCRIPTION OF SYMBOLS 1 Housing 2 Rod 3 Actuator 3a Electric motor 3b Deceleration mechanism 3c Linear motion mechanism 4 Controller 5 Displacement detection apparatus 10 Cylindrical body 11 Connection cover 12 Case 13 Lock nut 14 Snap ring 15, 16 Lid 20 Hollow rotating shaft 25 Motor cover 30 Planetary gear mechanism 34 Holder (cylindrical holding member)
36 Nut member 37 Bearing 40 Electronic circuit board 50 Magnet block 60 Support board 80a, 80b Power line 90 Signal line 100 Grommet 110 Support bracket

Claims (2)

In a vehicle rear wheel steering apparatus that is interposed in a suspension mechanism that supports a rear wheel of a vehicle and steers the rear wheel, a housing that is coupled to the suspension mechanism via a first coupling member and a second coupling member; An electric motor housed in a cylinder constituting the housing, a speed reduction mechanism housed in the cylinder and decelerating the output of the electric motor, a nut member connected to the speed reduction mechanism and rotating, and screwed into the nut member And a linear motion mechanism for converting the rotational motion of the nut member into linear motion of the rod, and the housing, and extending from the cylindrical body. arranged so as to surround the rod a housing fixed to the cylindrical body, and having at least one opening parallel to the opening on the rod, separate from the communication hole and the opening A housing having a lid bonded to seal the opening of the housing, wherein the controller is housed in the housing for driving and controlling the electric motor, the power line and a signal electrically connected to the controller a line, a grommet for holding by surrounding the said power lines and signal lines, and a support bracket to which the grommet is mounted, Rutotomoni those said power lines and signal lines are connected to the controller in the housing, the communicating A rear-wheel steering device for a vehicle, wherein the rear-wheel steering device is led out through a hole and the support bracket is fixed to the housing .   The controller includes an electronic circuit board on which a plurality of elements that drive and control the electric motor are mounted, and a support board that supports the electronic circuit board with a predetermined gap and is fixed to the housing. The vehicle rear wheel steering apparatus according to claim 1, wherein the power line and the signal line are joined to the electronic circuit board in the casing.

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